Blender 2.8 - AWS EC2 command line EEVEE render
The actual problem is that Eevee does not support headless rendering.

Besides that the command misses a flag that tells Blender to render. Right now it will just open the userpref.blend with your settings and then close. 

If you want to render the first frame, your command needs to contain -f 1.

blender -b -noaudio -E BLENDER_EEVEE -o . -F PNG -f 1


  -f, --render-frame &lt;frame&gt;
  
  Render frame  and save it.
  
  
  + start frame relative, - end frame relative.
  A comma separated list of frames can also be used (no spaces).
  A range of frames can be expressed using .. separator between the first and last frames (inclusive).
  


All flags can be found in Blender's manual.